TC7126_13 datasheet(13/28 Pages) MICROCHIP

Part #	TC7126

Description	3-1/2 Digit Analog-to-Digital Converters

PDF	28 Pages

Scroll/Zoom	100%

Manufacturer	MICROCHIP [Microchip Technology]

Direct Link	http://www.microchip.com

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13 / 28 page

 2002-2012 Microchip Technology Inc.

DS21458D-page 13

TC7126/A

6.6

Reference Voltage Selection

A full scale reading (2000 counts) requires the input

signal be twice the reference voltage.

Note:

VFS = 2VREF.

In some applications, a scale factor other than unity

may exist between a transducer output voltage and the

required digital reading. Assume, for example, a

pressure transducer output for 2000lb/in2 is 400mV.

Rather than dividing the input voltage by two, the

reference voltage should be set to 200mV. This permits

the transducer input to be used directly.

The differential reference can also be used where a

digital zero reading is required when VIN is not equal to

zero. This is common in temperature measuring instru-

mentation. A compensating offset voltage can be

applied between analog common and VIN-. The trans-

ducer output is connected between VIN+ and analog

common.

Required Full Scale Voltage*

VREF

20mV

100mV

TC7126 Datasheet(PDF) 13 Page - Microchip Technology